What's new in Siril 0.9.0 rc1

Siril 0.9.0 rc1 is the first release-candidate of the new version (2012-2015) of Siril. It is mainly a corrective update since the previous version 0.9.0 beta, which was itself a massive upgrade of the previous 0.8 version of 2006 (old website). Changes in this rc1 version over the beta include: